
var number = Math.round(7.4);//四舍五入;
alert(number);

var number1 = Math.random();//返回0-1之间的一个随机数;
alert(number1);

var number2 = Math.max(number,8);//返回number与8之间最大的数;
alert(number2);

var number3 = Math.min(number1,0.3);//返回number1与0.3之间最大的数;
alert(number3);

function cw() {
  window.open("https://www.baidu.com/");//点击按钮会弹出新的窗口;
}

setTimeout("alert('3秒!')",3000);//设置按时弹出弹框;

var cookie = document.cookie;
alert(cookie);
